In this episode Lord Drachenblut shows us how to start irssi in screen after reboot.
crontab -e # opens editor for crontab @reboot /usr/bin/screen -dmUS irc /usr/bin/irssi
-d -m Start screen in "detached" mode. This creates a new session but doesn't attach to it. This is useful for system startup scripts.
-U Run screen in UTF-8 mode. This option tells screen that your terminal sends and understands UTF-8 encoded characters. It also sets the default encoding for new windows to `utf8'.
-S sessionname When creating a new session, this option can be used to specify a meaningful name for the session. This name identifies the session for "screen -list" and "screen -r" actions. It substitutes the default [tty.host] suffix.